1. Field of the Invention
The present invention is generally related to a marine fuel system and, more particularly, to a fuel system that provides primary and secondary openings in a fuel conduit to allow fuel vapor to be removed from the cavity of a fuel reservoir.
2. Description of the Related Art
Those skilled in the art of marine propulsion systems are aware of many different types of fuel systems. Some fuel systems use fuel vapor separators which are vented while others use unvented reservoirs. Some systems incorporate lift pumps and high pressure pumps within the structure of a fuel reservoir while others place these pumps outside the fuel reservoir. Certain marine propulsion systems use separate pumps to lift fuel from a fuel tank and to pressurize the fuel and induce it to flow to a fuel injection system. In all types of marine propulsion systems, it is beneficial to control the accumulation of fuel vapor within the system and to moderate the temperature of the fuel under a wide variety of circumstances.
U.S. Pat. No. 4,844,043, which issued to Keller on Jul. 4, 1989, describes an anti-vapor lock carbureted fuel system. It includes a first crankcase pressure driven fuel pump supplying fuel from a remote fuel tank to a vapor separator, and a second crankcase pressure driven fuel pump supplying vapor free fuel from the vapor separator to the carburetors of the engine. In combination, a squeeze bulb and one-way check valve supply fuel from the remote fuel tank directly to the carburetors for starting the engine.
U.S. Pat. No. 4,848,283, which issued to Garms et al. on Jul. 18, 1989, discloses a marine engine with combination vapor return, crankcase pressure, and cooled fuel line conduit. A marine propulsion system includes a two-cycle water cooled crankcase compression internal combustion engine including a vapor separator, a remote fuel tank, and a fuel pump in the tank for delivering fuel to the engine in response to crankcase pulse pressure. A combination conduit between the fuel tank and the engine includes a first passage communicating crankcase pulse pressure from the engine to the fuel pump in the tank, a second passage supplying fuel from the pump in the tank to the engine, a third passage returning fuel vapor from the vapor separator at the engine back to the tank, a fourth passage supplying cooling water from the engine towards the tank, and a fifth passage returning water from the fourth passage back to the engine.
U.S. Pat. No. 4,856,483, which issued to Beavis et al. on Aug. 15, 1989, discloses a vacuum bleed and flow restrictor fitting for fuel injected engines with vapor separators. The fitting is provided in the vapor supply line. The fitting has a first reduced diameter passage providing a vacuum bleed orifice passage partially venting vacuum from the induction manifold to atmosphere, to limit peak vacuum applied to the vapor separator from the induction manifold. The fitting has a second reduced diameter passage providing a flow restrictor passage limiting the volume of flow of fuel vapor from the vapor separator to the induction manifold.
U.S. Pat. No. 4,876,993, which issued to Slattery on Oct. 31, 1989, discloses a fuel system with a vapor bypass of oil-fuel mixer halting oil pumping. The fuel delivery system has a vapor separator connected to prevent excess oil in the mixture as fuel runs out. The vapor separator has a fuel inlet receiving fuel from the tank, a fuel outlet delivering fuel to the fuel inlet of the oil-fuel mixer, and a vapor outlet delivering vapor or air through a bypass connection to the suction intake side of a fuel pump and bypassing the mixer.
U.S. Pat. No. 5,389,245, which issued to Jaeger et al. on Feb. 14, 1995, discloses a vapor separating unit for a fuel system. It has particular application to a fuel system for a marine engine. The vapor separating unit includes a closed tank having a fuel inlet through which fuel is fed to the tank by a diaphragm pump. The liquid level in the tank is controlled by a float-operated valve. An electric pump is located within the vapor separating tank and has an inlet disposed in the tank and an outlet connected to a fuel rail assembly of the engine.
U.S. Pat. No. 5,647,331, which issued to Swanson on Jul. 15, 1997, describes a liquid cooled fuel pump and vapor separator. The fuel pump is housed in an aluminum body module formed by two iso-pods open end to open end to provide a multi-cavity module housing of heat conductive material. The pump inlet faces downwardly in one of the cavities and a small clearance volume directly surrounds the pump casing which, in one embodiment, is filled with liquid fuel and in another with cooling water.
U.S. Pat. No. 5,832,903, which issued to White et al. on Nov. 10, 1998, discloses a fuel supply system for an internal combustion engine. It has an electronically controlled fuel injection system which eliminates the need for a vapor separator. The system pumps an excessive amount of fuel through a plumbed fuel supply loop and cools recirculated fuel to cool all the components in the plumbed fuel supply loop. Recirculated fuel flows from the pressure regulator to the water separating fuel filter as does make-up fuel from a fuel tank. The fuel stream from the water separating fuel filter flows to the low pressure side of the fuel pump which pumps the fuel through the plumb fuel supply loop.
U.S. Pat. No. 5,855,197, which issued to Kato on Jan. 5, 1999, describes a vapor separator for fuel injected engines. A compact vapor separator for a fuel injection system reduces the size of the fuel system mounted on the side of an outboard engine. The girth of the outboard motor's power head consequently is decreased. In one embodiment, the vapor separator employs a plurality of rotary vein type pumps. The pumps are sized to produce a sufficient flow rate and fuel pressure, while minimizing power consumption.
U.S. Pat. No. 5,908,020, which issued to Boutwell et al. on Jun. 1, 1999, describes a marine fuel pump and cooling system. It comprises a fuel pump, a fuel filter axially mounted directly below and around the lower portion of the fuel pump, and a spiral-wound fuel line composed of a heat conductive material mounted concentric to the upper portion of the fuel pump, minimizing the space required for installation.
U.S. Pat. No. 5,915,363, which issued to Iwata et al. on Jun. 29, 1999, describes a fuel supply system for an engine powering an outboard motor. The system includes a pump for supplying fuel from a tank to a vapor separator. Another pump delivers fuel from the vapor separator to at least one charge former for supplying fuel to the combustion chambers of the engine. The fuel supply system includes a mechanism for reducing the transmission of vapor to the pump which delivers fuel to the charge formers.
U.S. Pat. No. 6,006,705, which issued to Kato et al. on Dec. 28, 1999, describes a fuel injection system. It includes a main fuel source and a pump for delivering fuel from the main fuel source through a fuel filter to a vapor separator. Fuel is supplied from the chamber by a high pressure pump through a fuel rail to one or more fuel injectors. Undelivered fuel is returned to the vapor separator through a return line.
U.S. Pat. No. 6,076,509, which issued to Kyuma on Jun. 20, 2000, describes a fuel supply apparatus of an outboard motor. It comprises a vapor separator for removing bubbles in the fuel, a float type bubble discharge valve which is provided for the vapor separator and adapted to be closed when a fuel level in a fuel tank rises, and a negative pressure opening type valve connected to a downstream side of the bubble discharge valve so as to be opened upon reception of an intake negative pressure of the engine.
U.S. Pat. No. 6,216,672, which issued to Mishima et al. on Apr. 17, 2001, describes a fuel supply system of an outboard motor. It comprises a fuel tank in which a fuel is stored, a low pressure fuel filter and a low pressure fuel pump connected to the fuel tank through a fuel supply hose, a vapor separator connected to the low pressure fuel pump through a low pressure fuel hose, a high pressure fuel pump disposed inside the vapor separator, a pressure regulator disposed inside the vapor separator, a fuel hose having one end connected to the high pressure fuel pump, and a branch pipe incorporated on the way of the fuel hose and having one end connected to the pressure regulator.
U.S. Pat. No. 6,253,742, which issued to Wickman et al. on Jul. 3, 2001, discloses a fuel supply method for a marine propulsion engine. It uses a lift pump to transfer fuel from a remote tank to a vapor separator tank. Only one level sensor is provided in the vapor separator tank and an engine control unit monitors the total fuel usage subsequent to the most recent filling of the tank. When the fuel usage indicates that the fuel level in the vapor separator tank has reached a predefined lower level, a lift pump is activated to draw fuel from a remote tank and provide that fuel to the vapor separator tank.
U.S. Pat. No. 6,257,208, which issued to Harvey on Jul. 10, 2001, describes a marine vapor separator. A method of controlling fuel temperature while supplying fuel from a fuel tank to an array of fuel injectors of an internal combustion engine comprises the steps of pumping the fuel with a high pressure pump, flowing the fuel through a fuel line from the fuel tank to the high pressure pump, and flowing the fuel through a vapor separator in the fuel line between the tank and the high pressure pump.
U.S. Pat. No. 6,321,711, which issued to Kato on Nov. 27, 2001, describes a fuel supply system for a direct injected outboard engine. It includes a pump for supplying fuel from a tank to a vapor separator. An electrical pump delivers fuel from the vapor separator to a mechanical high pressure pump, which delivers fuel under high pressure to a fuel manifold and further to a pair of fuel rails. The fuel rails supply fuel to fuel injectors for delivering fuel to the combustion chambers of the engine.
U.S. Pat. No. 6,428,375, which issued to Takayanagi on Aug. 6, 2002, describes a fuel cooling apparatus of an outboard motor. It has a vapor separator, a fuel injector positioned to supply a fuel from the vapor separator into the engine, a high pressure fuel pump positioned in the vapor separator to feed the fuel under pressure to the fuel injector, and a pressure regulator positioned in the vapor separator to reduce a pressure of a return fuel, the fuel cooling apparatus including a fuel cooler having fuel and cooling water passages arranged side by side.
U.S. Pat. No. 6,553,974, which issued to Wickman et al. on Apr. 29, 2003, discloses an engine fuel system with a fuel vapor separator and a fuel vapor vent canister. The system provides an additional fuel chamber, associated with a fuel vapor separator, that receives fuel vapor from a vent of the fuel vapor separator. In order to prevent the flow of liquid fuel into and out of the additional fuel chamber, a valve is provided which is able to block the vent of the additional chamber.
U.S. Pat. No. 6,575,145, which issued to Takahashi on Jun. 10, 2003, describes a fuel supply system for a four cycle outboard motor. It includes a fuel injection system that includes a fuel pump, a plurality of fuel injectors, a fuel pump and a vapor separator. The vapor separator is in communication with a fuel pump and at least one fuel return line. The vapor separator includes a vent for removing vapors from the fuel. The vapor separator also includes a canister positioned within the vapor separator below the vent. The canister includes hydrocarbon absorption media.
U.S. Pat. No. 6,679,229, which issued to Wada et al. on Jan. 20, 2004, describes a fuel supply apparatus for an outboard engine. To improve a freedom of layout within a narrow cowling of an outboard engine, achieve a reduction of manufacturing costs and an improvement of a maintenance performance of a fuel filter, a fuel supply apparatus in an outboard engine is structured such that fuel within a fuel tank is supplied into a vapor separator via a to low pressure fuel pump.
U.S. Pat. No. 6,698,401, which issued to Suzuki et al. on Mar. 2, 2004, describes a fuel supply control system for an outboard motor. It regulates the fuel pressure to a vapor separator in a fuel injection system by using a pressure relief valve that returns excess fuel to the intake of the fuel pump. In order to permit excess fuel flow without substantial excess in low speeds, the fuel pump speed is regulated depending upon engine speed, fuel temperature, and fuel pressure.
U.S. Pat. No. 6,918,380, which issued to Nomura on Jul. 19, 2005, describes a fuel injection apparatus for a marine engine. To provide a fuel injection apparatus preferable for a marine engine which can prevent a metal soap from being generated in a motor portion of a high pressure electric pump even when fuel containing sea water is sucked into the electric pump, a high pressure electric pump is provided with a pump portion and a motor portion within a pump housing, the pump portion sucks fuel within a vapor separator, high pressure fuel the pressure of which has been increased by the pump portion is discharged through a periphery of the pump portion.
U.S. Pat. No. 7,101,239, which issued to Torgerud et al. on Sep. 5, 2006, discloses a fuel filter located below an adapter plate of an outboard motor. A marine propulsion device is provided with a fuel filter that is connectable between a fuel tank and a fuel pump, wherein the fuel filter is disposed below an adapter plate of the marine propulsion device. The adapter plate is located between the fuel filter and the engine so that the fuel filter is not located under the cowl of the marine propulsion device where an engine is housed.
U.S. Pat. No. 7,168,414, which issued to Harvey on Jan. 30, 2007, describes a marine vapor separator with a bypass line. Liquid fuel is to supplied to a marine engine from a fuel tank. The fuel first passes through a water filter, a lift pump and is temporarily deposited in a vapor separator where vapors given off from the fuel are collected and vented. A high pressure pump withdraws liquid fuel from the vapor separator and delivers it under pressure to an engine injection system via a fuel delivery line.
U.S. Pat. No. 7,178,512, which issued to Merten on Feb. 20, 2007, discloses a fuel system for a marine vessel with a gaseous purge fuel container. A fuel container for a marine propulsion system is provided with a pump and a hose connected to an outlet of the pump and disposed within the cavity of the fuel container. The hose is provided with an opening, formed through its wall, through which a fluid can flow under certain circumstances. The opening is disposed in an ullage within the container and allows gaseous elements to be purged from the container when flow is induced from the container back to a fuel reservoir.
U.S. Pat. No. 7,401,598, which issued to Ochiai on Jul. 22, 2008, describes an outboard motor with forward air intake and air cooled fuel pump. It comprises a cowling for covering an engine, a high pressure fuel supply system, and a low pressure fuel supply system. The high pressure fuel supply system can have a vapor separator tank and a high pressure fuel pump. The low pressure fuel supply system can have a low pressure fuel pump. A heat insulating chamber, defined from a space for accommodating the engine, can be formed within the cowling. The heat insulating chamber houses the low pressure fuel pump and the fuel filter.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
As described above, many different types of fuel supply systems are known to those skilled in the art. It is important to control the temperature of fuel that is drawn from a fuel tank and supplied to an engine located under the cowl of an outboard motor. It is also necessary to control the accumulation of fuel vapor within the conduits and reservoirs of the fuel system. It would therefore be significantly beneficial if a relatively simple system could be provided which controls the amount of gaseous fuel vapor contained within a fuel reservoir, which moderates the temperature of stored fuel within the reservoir or which is recirculated by its associated fuel pumps, and which separates fuel circulated by one fuel pump from fuel circulated by the other fuel pump.